Thanks for the info. I will follow up on Sanning. About a decade ago I was surprised to read in a book by Ian Kershaw that there was no document that signaled the start of the mass slaughter of Jews in the east.

Hopefully, if truth reasserts itself in this post-truth world, an investigation into this episode of history will take place. If not, we'll have to hope for a curious Chinese scholar to lift up and look under the rocks.